Description: (Adapted from the application) The Core Laboratory for Protein Microsequencing and Mass Spectrometry will be a new addition to the DERC core grant. Support is requested to further enhance and expand an already well-established self-supporting core laboratory located on the Worcester Foundation Campus of the University of Massachusetts Medical School. The Laboratory currently provides protein microcharacterization services. Such services include microsequence analysis by means of automated Edman Degradation chemistry and Matrix-Assisted Laser Desorption/lonization Time-of-Flight (MALDI-TOF) mass spectrometry. More specifically, MALDI-TOF mass spectrometry is being used to identify proteins by mass analysis of enzymatic digests. As many genome projects come to completion, identification of the expressed proteins (Proteome) by mass spectrometric techniques becomes the most feasible approach due to both its speed of analysis and sensitivity. The Institute has committed to the purchase of an electrospray quadruple ion trap mass spectrometer that has superior capabilities to what already exists in the analysis of peptide masses and subsequent data base searching. The new instrumentation has the capability of analyzing both complex protein mixtures as well as some limited use in de novo sequencing. Many DERC investigators are studying proteins involved in signal transduction pathways as well as the polypeptide components of large multisubunit protein complexes which constitutes many cell organelles. Since many of the model organisms used by DERC investigators have well characterized genomes, we plan to exploit the mass spectrometric techniques to rapidly identify these proteins and characterize some of their post translational modifications (i.e., phosphorylation sites). To accomplish these goals we are requesting some support for the laboratory's director, the new instrumentation, and a technical assistant so that protein characterization services can be offered at a highly subsidized rate to DERC investigators.